The following correction was printed in the Guardian's Corrections and clarifications column, Friday October 20 2006

In early editions of the article below, we referred to a letter from Bob Ward of the Royal Society that expressed particular concern "about $2.9bn (£1.5bn) of funding to 39 groups deemed by the academy to misrepresent the science of global warming". Those figures should have been expressed as millions not billions.

ExxonMobil has escalated a row with the Royal Society by accusing it of "inaccurately and unfairly" depicting the world's largest oil company as a climate change sceptic.

However, Exxon admits it is reviewing the funding of various outside groups which were accused by the Royal Society of undermining the scientific consensus on global warming.

An unprecedented letter from the UK's premier scientific academy to Exxon was quoted in the Guardian this week, criticising it for making "inaccurate and misleading" statements on climate change.

Yesterday Exxon retaliated, saying: "The Royal Society's letter and public statements to the media inaccurately and unfairly described our company."

It went on: "We know that carbon emissions are one of the factors that contribute to climate change - we don't debate or dispute this."

The letter from Bob Ward of the Royal Society expressed particular concern about $2.9m (£1.5m) of funding to 39 groups deemed by the academy to misrepresent the science of global warming. It mentioned the George C Marshall Institute, which argued in a 2004 report that "there is not a robust basis" for concluding what impact human influence was having on the future of the climate.

Another group, the US Competitive Enterprise Institute, has responded to the release of Al Gore's climate change film, An Inconvenient Truth, with adverts welcoming increased CO2 emissions.

Exxon said yesterday: "Contrary to the inferences made in the recent reports in the media and allegations by the Royal Society, ExxonMobil had no involvement with the CEI's advertisements, nor in the Al Gore film spoof."

The oil group said it agreed with scientific assessments which conclude that climate change poses risks which may prove to be significant for society and ecosystems. This was why it was taking steps to reduce carbon and other greenhouse gas emissions from its own operations.

But Exxon admits it still has reservations about the issue because certain "uncertainties" exist. "We support approaches to reduce emissions more broadly in ways that are cost effective for society and that consider the uncertainties that remain," it said.

Despite its rejection of the Royal Society arguments, Exxon said it was reviewing the funding of all outside groups which received money from it, but insisted this was an annual event.